Liquid pump



Aug- 12, 1941. aw. 1-1.0. BENNE+ Em 2,252 244 LIQUID PUMP Filed Oct. 14,1940 In verz f0 7'.

W m M 2 viz L4 4% Patented Aug. 12, 1941 LIQUID PUMP Carl Wilhelm HenrikDiicker Bennet and Anders Johan Emil Rylander, Stockholm,Swedemassignors to Louise Gunnila Violet Bennet, Runeborg, Stocksund,Sweden Application October 14, 1940, Serial No. 381,175 In SwedenOctober 13, 1939 3 Claims.

(Granted under the provisions of sec. 14, act of March 2, 1927; 357 0.G. 5)

Our invention relates to liquid pumps of the type comprising a casingand a flexible wall therein adapted to perform uni-directional wavelikemovements with the crests of the wave in contact with a wall of thecasing. The invention has for its object to provide a pump of the typereferred to adapted to be operated without interruption even if theliquid to be pumped contains solid particles of varying sizes, as isoften the case in, for instance, bilge-pumps or dock pumps. Theinvention is an improvement over the subject matter embodied in theBennet application Serial No. 280,193, filed June 20, 1939.

We attain this object by mechanism illustrated in the accompanyingdrawing, in WhlCi'l- Fig. 1 is a cross-sectional view taken on the lineI--I of Fig. 2 of a liquid pump constructed in accordance with theinvention, and Fig. 2 is a plan view of the pump, the cover thereofbeing removed.

The pump comprises an oblong casing ill of rectangular cross-section anda cover being suitably secured to the casing. At the end walls of thecasing, there are provided bearings l2 and i3 for a helically shaped rodis hereinafter termed the helix. On either side of the helix there isprovided a flexible band l5 and It, respectively, which constitutedisplaceable Walls positioned within the casing. The ends of said bandsare secured to the bearings 12 and I3. The bands extend throughout theheight of the casing so as to engage the cover II and the bottom wall ofthe casing with a tight fit. The distance between the ends of each bandis so much less than the actual lengths of the bands that they are incontact with the helix l4 throughout the whole length thereof. Thecasing is provided with connections l8, I9, 20 which communicate withthe interior of the casing and serve as inlets and outlets for theliquid.

The crests of the band abut normally with a tight fit against lateralWalls 2| and 22 which together with the cover and the bottom wall of thecasing enclose the working chambers of the pump. The walls 2| and 22 canbe displaced laterally and outwardly against the resistance of helicalsprings 23 while maintaining their sliding fit with the cover and thebottom wall of the casing, the springs 23 being inserted between saidmovable walls and the stationary side walls of the casing. The movableWalls 2| and 22 are normally kept in the position shown in the drawingby the action of the springs 23 forcing said walls against stationaryabutments 24 the position of which is determined such that the crests ofthe bands l5 and I6 can slide on. the walls 2| and 22, respectively.

If rotation is imparted to the helix M, the bands will be actuated soasto perform unidirectional wave-like movements with their crests incontact with the walls 2| and 22, each band acting as an endless pistonhaving a continuous uni-directional movement. Consequently, theapparatus will work as a displacement pump propelling a constantquantity of liquid for each revolution of the helix. The workingchambers 25 and 26 confined by the bands and the movable walls will thusbe moved in a certain direction depending upon the direction of rotationof the helix, for instance from. the inlets l1, l8 to the outlets l9 and20, respectively, and the liquid enclosed in said chambers will bepropelled in the said direction. Obviously, the pressure exerted by thesprings 23 on the movable walls 2| and 22 should be somewhat higher thanthe pressure exerted by the liquid enclosed in the working chambers soas to maintain the walls 2| and 22, under normal operation, in thepositions shown in the drawing.

If, for some reason or other, a solid particle, such as a pebble or apiece of wood or metal, is drawn by suction into one of the workingchambers, an excessive pressure will be set up at the place where one ofthe crests during its unidirectional movement comes into contact withthe particle. Due to the said excessive pressure the respective wall 2|or 22 will be moved laterally outwardly against the action of thesprings 23. As a result thereof, the particle can be moved into theoutlet by the action of the crest travelling from the inlet to theoutlet Without any detrimental effect on the movable parts of the pumpand without interruption of the operation of the pump. When the abovenamed excessive pressure ceases the movable wall will be returned, bythe action of the springs 23, into its normal position shown in thedrawing.

Instead of providing relatively high-compression spring members 23between the movable and stationary walls, the spaces between the saidwalls may be brought into communication with the outlet, as indicated bythe pipe 21 (Fig. 2). As a result thereof, the pressures prevailing oneither side of the movable Wall will substantially counterbalance eachother irrespective of variations in the pump pressure, and the springs23 can be replaced by low-compression springs.

While we have shown an embodiment of the invention comprising twoflexible bands, and

two working chambers arranged in parallel and in which the lateral wallsare movable out of contact with the crests of the flexible band, it willbe understood that the invention is not limited to the specific detailsthereof described with reference to the drawing.

What we claim is:

1. A pump comprising a working chamber, a flexible wall in said chamber,means for imparting to said displaceable wall a uni-directionalwave-like movement, a second Wall arranged to abut a crest of saiddisplaceable wall, said walls being spaced from each other so as toconstitute the working chamber, and resilient means arranged normally tomaintain said second wall in contact with said crest and to permit saidsecond wall of being removed from said crest due to excessive pressureon said second Wall.

2. A pump comprising a casing, a working chamber in said casing, adisplaceable wall in said chamber, means for imparting to said flexiblewall a uni-directional wave-like movement, a movable wall slidable insaid casing and arranged to abut a crest of said displaceable wall, saidwalls being spaced from each other so as to constitute the workingchamber, resilient means arranged normally to maintain said movable wallin contact with said crest and to permit said movable wall of beingremoved from said crest due to excessive pressure on said movable wall,and abutting means for maintaining said movable wall in normal position.

3. A pump comprising a casing, a working chamber in said casing, aflexible wall in said chamber, means for imparting to said flexible walla uni-directional wave-like movement, a movable wall slidable in saidcasing and arranged to abut a crest of said flexible wall, said wallsbeing spaced from each other so as to constitute the working chamber,resilient means arranged normally to maintain said movable wall incontact With said crest and to permit said movable wall of being removedfrom said crest due to excessive pressure on said movable wall, a secondchamber in said casing bounded by said movable wall, and means forconducting working fluid to said second chamber.

CARL VVILHEIM HENRIK DUCKER, BENNET. ANDERS J OHAN EMIL RYLANDER.

